Cardboard-based unit

ABSTRACT

The present disclosure provides a cardboard-based unit, structural elements comprising said unit and land-vehicles comprising said units and structural elements.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/533,841 filed on Nov. 5, 2014, which is a continuation-in-part of PCTPatent Application No. PCT/IL2013/050823, filed on Oct. 13, 2013, whichclaims the priority benefit under 35 U.S.C. §119 of U.S. ProvisionalApplication No. 61/818,611 filed May 2, 2013, the contents of which arehereby incorporated in their entireties by reference.

TECHNOLOGICAL FIELD AND BACKGROUND

The present disclosure relates to units substantially or entirely madeof cardboard that may be used as structural elements in structures anddevices such as wheeled devices (e.g. bicycle or tricycle).

WO11067742 discloses a human-powered land vehicle sufficiently rigid soas to transport a human rider. The vehicle is constructed from pulpablyrecyclable and shreddably recyclable materials.

GENERAL DESCRIPTION

The present disclosure provides, by a first of its aspects, a structuralunit made from or comprising cardboard as its major component. Thismeans that cardboard constitutes typically at least about 60%, 65%, 70%,75%, 80%, 85%, 90%, and at times even at least 95% of the total weightof the structure. The unit comprises, as will be illustrated below, lowdensity cardboard layers.

By a first aspect, the unit of this disclosure comprises reinforcing,elongated members that may be made of cardboard, e.g. may be cardboardcylinders or rods; or may be made of other light materials, such as woodor plastic. The elongated members are then wholly or partially envelopedby portions of the low density cardboard panel formed to be in tightassociation with said elongated members. Some other portions of thecardboard panel are associated with one another to define a multi-layercardboard element.

By a second aspect, the multi-layer cardboard unit comprises a highdensity cardboard layer. For example, two low density cardboard layersmay sandwich a high density cardboard layer. A particular example is a3-layer structure with two external layers of low density cardboardsandwiching a high density cardboard layer.

A unit of this disclosure may also combine features of both aspects,namely comprising one or more such elongated members as well as a highdensity cardboard layer sandwiched between two low density cardboardlayers.

Said elongated members with the associated portions of the cardboardpanel jointly form a core-envelope element. The core-envelope elementmay be situated at and define edges of a multi-layer planar unit. Thecore-envelope element has usually also a functional significance inreinforcing the structural rigidity in bend, compression and tensionresistance disclosure, as will also be explained further below. Thestructure of the disclosure may constitute a part of a device, such as awheeled device, e.g. parts of a bicycle or tricycle.

The disclosure, thus provides, by the first aspect, a substantiallyplanar, cardboard-based unit comprising (i) two or more layers ofcardboard that are closely associated, typically adhered, with oneanother and that may be constituted by a formed low-density cardboardpanel, and comprising (ii) two or more integral core-envelope elements,each comprising enveloping portions of the low density cardboard thatare tightly associated with corresponding two or more elongated members.For example, the unit may be constituted from a formed cardboard panelthat is wrapped about the elongated members, with portions of the panelfacing one another are tightly associated with one another, e.g. by anadhesive.

Provided, by the second aspect of this disclosure, is a unit comprisinga high density cardboard panel sandwiched between two layers oflow-density cardboard.

The combination of one or more layers of a high density cardboard,particularly when tightly sandwiched between two layers of low-densitycardboard as provided by the second aspect, provides for additionalreinforcement, especially against compression or deformation in adirection normal to the plane of the cardboard layers, as compared tosuch a unit that has a similar layers' structure but devoid of the highdensity cardboard layer.

It should be noted that the structural unit may also comprise anexternal varnish or other coating layer. The reference made herein to amulti-layer structure excludes such layers and focuses on the structuralelements of the unit. Thus, for example, a unit with a 3-layer cardboardstructure may also comprise additional coating layers.

Generally, the term “elongated” means that the element has a lengthdimension that is significantly more prominent than other measurementsof the element. Such an element may generally have the structure similarto that of the elongated element disclosed in co-owned PCT applicationhaving the publication number WO2014/061012 (hereinafter: “the '012 PCTapplication”). One or both of the panel portions embracing the elongatedmember (referred to therein as the “rectangular sub-structure”) isintegral with panel portion that forms other parts of the structure.

The term “cardboard panel” means a planar or substantially planarcardboard piece with a broad surface that is substantially thin ascompared to its length and width. The cardboard panel may be a uniformcardboard piece but may also, for example, be made of two or more planarcardboard pieces glued or otherwise adhered together to form a largercardboard panel that is formed into the unit's different elements.

The term “formed” (or any of its linguistic variations) means to denotethe act of giving form or shape to the cardboard panel, namely formingthe panel into a final intended shape in the unit. Such formingcomprises, for example, wrapping a portion of the panel over theelongated member to thereby obtain the core-envelope structure of theso-formed elongated element. Such forming may also comprise, in someembodiments, defining voids in said planar element.

The term “integral” means that the panel portions that are used in theformation of the different elements are all portions of a single, formedpanel. Thus, for example, in the case of a panel portion that isenveloping the elongated member, defining two skirts of the panelextending from an apex defined along the elongated member, at least oneor both of the skirt portions of the panel extends into other portionsof the panel that define one or more other elements of the unit.

As noted, portions of the panel according to said first aspect arewrapped about two or more elongated members such that the panel comesinto tight association with said members to thereby define saidelongated, core-envelope elements. The elongated core-envelope element,formed through the association between the elongated member and theenveloping cardboard panel, may impart an increased rigidity, e.g. bend,tension and compression resistance to the cardboard structure, ascompared to rigidity and said resistance of a similar cardboardstructure that does not include such elongated core-envelope elements.Said elongated core-envelope element may define an edge of a planarmulti-layer (e.g. bi-layer) cardboard unit. Typically, two suchelongated core-envelope elements define edges of a substantially planarelement that extends therebetween.

The elongated members (which, as noted above, may be made of cardboard,wood or plastic) typically have a rounded shape, e.g. circularcross-section (although at times it may be oval, elliptical, etc.); andaccordingly said elongated core-envelope elements are typically rounded,although they may be shaped by the use of appropriate dies into othershapes, e.g. to have a substantially rectangular externalcross-sectional shape.

The disclosure embodies some features, common with those of the '012 PCTapplication as well as of another PCT application Ser. No.PCT/IL2013/050823, the relevant contents of both incorporated herein byreference.

The cardboard-based unit of the first aspect of this disclosure has a 3-or 4-point bending strength normal to said elongated core-envelopeelements that is significantly larger than that of a cardboard structuredevoid of such elongated core-envelope elements. The term “significantlylarger” means that it is at least two, five and, at times, at least10-fold larger than that of either the reinforcing members or theregular bi-layer cardboard structure, one without the elongated members.Some explanations and parameters concerning this bend resistance can befound in the '012 PCT application, the contents of which, as notedabove, is incorporated herein by reference for the relevant portionsthereof.

The “low density cardboard panel” denotes a cardboard panel comprising(i) at least one low-density layer made of paper, high density paper orcardboard (for ease of reference the term “paper”, will be usedhereinafter to refer collectively to paper, high density paper orcardboard) arranged to define a plurality of cells or voids, e.g.,formed by corrugated, fluted or otherwise loosely packed paper sheets orstrips that define a plurality of voids therebetween, and comprising(ii) one or more liner cardboard sheets lined at one side or both sidesof the low-density layers (namely sandwiching the low-density layerbetween them). Examples of such cardboard panels are such known as“corrugated cardboard”, which consists of a fluted or corrugated paperpanel(s) or strip and one or two flat linerboards at one or both (i.e.sandwiching) sides of the fluted or corrugated paper; and may also besuch referred to as “honeycomb cardboard”. Such materials are widelyused in the manufacture of boxes and shipping containers. The corrugatedor honeycomb cardboard panels may be single-walled or multi-walledcardboard panel.

The term “high density cardboard” denotes a cardboard panel that issubstantially uniform throughout its cross-section. A high densitycardboard does not have a low-density layer of the kind described above.

By one embodiment of the first aspect, the cardboard-based unitcomprises two first elongated core-envelope elements that are parallelto one to the other, being formed with corresponding parallel elongatedmembers. Such first elongated core-envelope elements define edges of aplanar element that extends therebetween. The first elongatedcore-envelope elements are associated to corresponding first parallelelongated members. Said first elongated members may separate eachbetween a central segment of the original cardboard panel and one offirst or second flanking segments that flank the central segment; theflanking segments and the central segment, once a portion of the panelis wrapped over the elongated members, jointly form a two-layer element.

According to one embodiment, one or more portions of a first face of thefirst flanking segment are attached to one or more portions (opposite inthe formed structure) of the first face of the central segment. Byanother embodiment, one or more portions of the first face of the firstflanking segment and one or more portions of the first face of thesecond flanking segment are both attached to corresponding portions ofthe first face of the central segment. According to this embodiment atleast two parallel elongated members are associated with the first faceof the panel. The structure is typically formed such that opposite edgesof the original panel, being the edges at the end of the flankingsegments, are brought into proximity with one another. In this manner aclosed loop structure (as can best be seen in a cross-section) is formedby the panel, with the first elongated core-envelope elements definingthe extreme ends of such a loop.

By another embodiment, rather than forming a closed loop structure, acardboard panel is folded into a form generally resembling an “S” shapewith oppositely oriented folds. In such a configuration, one or moreportions of a first face of the first flanking segment is attached tocorresponding one or more portions of the first face of the centralsegment; while one or more portions of the second face of the centralsegment is attached to corresponding one or more portions of the secondface of the second flanking segment. In this configuration, theelongated members within the first parallel elongated core-envelopeelements are associated one with the first face and the other with thesecond face of the panel.

By one embodiment such a planar cardboard unit is substantially uniformwith a complete cardboard multi-layer structure over the entire surface.In another embodiment, one or more voids are formed in this planarcardboard element, which may have decorative or functional significance,e.g. through cut-outs from the multi-layer cardboard element or throughappropriately forming of the original cardboard panel.

In accordance with one embodiment, the cardboard-based unit comprisesone or more integral second elongated, core-envelope elements (formed bya portion of the cardboard panel that is wrapped about an elongatedmember oriented normal to said first elongated core-envelope elements.

In accordance with some embodiments, the cardboard-based unit of thisdisclosure (of both the first and the second aspects) constitutes partof a wheeled device or a land vehicle, such as a bicycle or tricycle.

Provided by a third aspect this disclosure is a vehicle, such as atricycle or bicycle comprising a structural unit of the kind describedherein. A particular example is a bicycle of the kind known as a“balance bike” or “run bike”, which is a training bicycle, intendedprimarily for children, having no pedals or drive chain, and where therider (typically the child) propels itself by pushing the ground withhis/her feet. In such a bicycle or tricycle the body may be a structuralunit with the characteristics of that of this disclosure. Also, oralternatively, the front wheel steering frame may also be a structuralunit with the characteristics of that of this disclosure.

By one embodiment the fork assembly has a fork with the characteristicsof a structural unit according to the first aspect, with or without anadditional high density cardboard panel sandwiched between the two lowdensity cardboard panels; and the body has the characteristics of astructural unit according to the second aspect.

Provided by an embodiment of the invention is a bicycle that comprises(i) a body that extends between a front end and a rear end of thebicycle with a rear wheel that is fitted at the rear end of the body,namely at the end itself or close to it, and (ii) a fork assembly thatis pivotally coupled to the body and having a front wheel that isrotationally fitted to said fork. The body and the fork assemblycomprise each an element that has the characteristics of the unitsdisclosed herein. The body and the fork assembly are typicallyconstituted entirely out of cardboard and have the characteristics ofsaid units.

By one embodiment the body comprises a planar body element embodying thecharacteristics of the unit of the second aspect of this disclosure andthe fork assembly comprising an element embodying the characteristics ofthe unit of the first aspect of this disclosure.

An exemplary bicycle, e.g. a training bike, has the followingcharacteristics:

(i) a body that comprises two planar body elements, each defining avertical plane and are, typically, mirror images of one another andhaving both a front end and a rear end, the two body elements beingattached to one another at their front end portion to define a frontbody block and diverge from one another towards the rear end to therebydefine a body space between them; each of said elements embodying thecharacteristics of the unit of said second aspect;

(ii) a rear wheel fitted within the body space and being rotationallycoupled to the two panels at a rear end thereof by a horizontal axlethat is received within co-axial bushings (typically, but notexclusively, made of plastic) fitted in said panels;

(iii) a steering assembly comprising a planar fork member embodying thecharacteristics of the unit of the first aspects and formed by cut-outsto define (1) a fork portion with two stems defining between them a stemspace, and (2) a panel opening in a mid-portion of the panel;

(iv) a vertical pivot-accommodating receptacle formed within said frontbody block and accommodating a pivot that extends vertically through thepanel opening between bushings (typically, but not exclusively, made ofplastic) formed at opposite edges of said opening to hinge said fork tosaid body; and

(v) a front wheel fitted within the stem space and being rotationallycoupled to the two stems by a horizontal axle that is received withinco-axial bushings fitted in said stems.

EMBODIMENTS

Some exemplary embodiments are defined in the numbered paragraphs below.The description of these embodiments is not intended to derogate butrather to add onto the general description above and the detaileddescription that follows.

-   1. A unit, comprising

one or more substantially planar elements comprising two or more layersof low density cardboard that are closely associated with one another,particularly such that are constituted from a formed low densitycardboard panel; and

two or more integral core-envelope elements that comprises envelopingportions of the low density cardboard that are tightly associated withcorresponding two or more elongated members.

-   2. The unit of embodiment 1, wherein the cardboard layers in said    planar elements are attached to one another at portions thereof.-   3. The unit of embodiment 1 or 2, wherein said elongated members    have a rounded cross-section.-   4. The unit of embodiment 3, wherein said elongated members have a    circular cross-section.-   5. The unit of any one of embodiments 1-4, wherein said elongated    members are made of wood, cardboard or plastic.-   6. The unit of any one of embodiments 1-5, wherein said cardboard    panel comprises (i) at least one low-density layer and (ii) one or    more liner cardboard sheets lining at least one side of the at least    one low-density layer.-   7. The unit of embodiment 6, wherein the low-density cardboard is    corrugated cardboard or honeycomb cardboard.-   8. The unit of any one of the embodiments 1-7, wherein said    elongated core-envelope elements impart an increased rigidity and    bend resistance to the cardboard unit.-   9. The unit of any one of the embodiments 1-8, wherein said    elongated core-envelope elements define edges thereof.-   10. The unit of embodiment 9, wherein said edges have a rounded    external cross-sectional shape.-   11. The unit of any one of embodiments 1-10, wherein two of said    elongated core-envelope elements are parallel one to the other.-   12. The unit of embodiment 11, wherein the two parallel elongated    core-envelope elements define edges of a substantially planar    structural element that extends therebetween.-   13. The unit of any one of embodiments 1-12, wherein two flanking    segments of a panel are folded over the elongated members and are    associated with a central segment of the panel that is defined    between said elongated members.-   14. The unit of embodiment 13, wherein one or more portions of one    face of said first flanking segment are attached to one or more    portions of the same face of said central segment.-   15. The unit of embodiment 13 or 14, wherein the panel has first and    second faces and wherein the first face of the two flanking segment    are attached to the first face of said central segment.-   16. The unit of embodiment 14 or 15, wherein the elongated members    are associated with the same face of the panel.-   17. The unit of any one of embodiments 13-16, wherein

the panel has first and second faces,

the first face of each of the flanking segments is associated with thefirst face of the central segment, and wherein

opposite edges of the panel, at the end of said flanking segments, areproximal to one another.

-   18. The unit of embodiment 13 or 14, wherein

one or more portions of a face of one flanking segment are attached tocorresponding one or more portions on the same face of said centralsegment, and

one or more portions of said second flanking segment are attached tocorresponding one or more portions of the opposite face of said centralsegment.

-   19. The unit of embodiment 18, wherein

one of the parallel elongated members is associated with one face of thepanel, and

the other of the parallel elongated members is associated with theopposite face of the panel.

-   20. The unit of any one of the embodiments 1-19, wherein said planar    element comprises one or more voids.-   21. The unit of any one of embodiments 11-20, comprising one or more    integral second core-envelope elements oriented normal to said    parallel elongated core-envelope elements.-   22. The unit of any one of embodiment 1-21, comprising a high    density cardboard panel sandwiched between two layers of low-density    cardboard.-   23. A structural unit having a planar element that comprises a high    density cardboard layer sandwiched between two layers of low-density    cardboard.-   24. The unit of embodiment 23, wherein the two layers of low density    cardboard that sandwich a high layer are formed from a single folded    cardboard panel.-   25. The unit of embodiment 23 or 24, wherein each layer is adhered    to a neighboring layer.-   26. The unit of any one of embodiments 23-25, being shaped according    to structural requirements by cut-outs in the planar element.-   27. The unit of any one of embodiments 1-26, being part of a wheeled    device.-   28. The unit of embodiment 27, wherein the wheeled device is a    bicycle or tricycle.-   29. The unit of embodiment 27 or 28, having the following    characteristics:

being a fork of a bicycle or tricycle and configured for coupling with(i) a front wheel and (ii) one or more other parts of the bicycle ortricycle.

-   30. The unit of embodiment 29, comprising a core-envelope element    integral with said planar element and configured as a handlebar of    the bicycle or tricycle.-   31. The unit of any one of embodiments 1-30, comprising at least one    hollow elongated member.-   32. The unit of embodiment 31, wherein at least one of the hollow    elongated members is cylindrical and accommodates an axle.-   33. A land vehicle comprising a structural unit as defined in any    one of embodiments 1-32.-   34. The land vehicle of embodiment 33, being a bicycle or tricycle.-   35. The land vehicle of embodiment 34, being a balance bike.-   36. The land vehicle of embodiment 34 or 35, comprising a    front-wheel steering unit having the characteristics of a unit of    any one of embodiments 1-32.-   37. A bicycle comprising a body extending between a front end and a    rear end, a fork pivotally coupled to the body, a front wheel fitted    to said fork, and a rear wheel fitted at the rear of said body, the    body and the fork assembly comprising each an element having the    characteristics of the unit of any one of embodiments 1-32.-   38. The bicycle of embodiment 37, wherein

the body comprises a planar body element embodying the characteristicsof the unit of any one of embodiments 23-25; and

the fork assembly comprises an element embodying the characteristics ofthe unit of any one of embodiments 1-22.

-   39. A bicycle comprising:

a body extending between a front end and a rear end, a fork pivotallycoupled to the body, a front wheel fitted to said fork and a rear wheelfitted at the rear of said body.

the body and the fork assembly comprising each an element having thecharacteristics of the unit of any one of embodiments 1-32.

-   40. The bicycle of embodiment 39, wherein

the body comprises a planar body element embodying the characteristicsof the unit of any one of embodiments 23-25; and

the fork assembly comprising an element embodying the characteristics ofthe unit of any one of embodiments 1-22.

-   41. A bicycle, comprising:

a body that comprises two planar body elements, each defining a verticalplane and are, typically, mirror images of one another and having both afront end and a rear end, the two body elements being attached to oneanother at their front end portion to define a front body block anddiverge from one another towards the rear end to thereby define a bodyspace between them; each of said elements embodying the characteristicsof the unit of any one of embodiments 23-25;

a rear wheel fitted within the body space and being rotationally coupledto the two panels at a rear end thereof by a horizontal axle that isreceived within co-axial bushings fitted in said panels;

a steering assembly comprising a planar fork member embodying thecharacteristics of the unit of any one of embodiments 1-22 and formed bycut-outs to define

-   -   a fork portion with two stems defining a between them a stem        space, and    -   a panel opening in a mid-portion of the panel;

a vertical fork pivot-accommodating receptacle formed within said frontbody block and accommodating a pivot that extends vertically through thepanel opening between bushings formed at opposite edges of said openingto hinge said fork to said body; and

a front wheel fitted within the stem space and being rotationallycoupled to the two stems by a horizontal axle that is received withinco-axial bushings fitted in said stems.

-   42. The bicycle of embodiment 41, wherein one or more of the    bushings, typically all of them, are made of plastic.-   43. The bicycle of embodiment 42, being a training bike.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand the subject matter that is disclosedherein and to exemplify how it may be carried out in practice,embodiments will now be described, by way of non-limiting example only,with reference to the accompanying drawings, in which:

FIG. 1A is a schematic representation of the manner of production of acardboard-based unit according to an embodiment of the disclosure.

FIGS. 1B and 1C show, respectively, a schematic perspective view and aview from above, of the so formed unit.

FIG. 2A is a schematic representation of the manner of production of acardboard-based unit according to another embodiment of the disclosure.

FIGS. 2B and 2C show, respectively, a schematic perspective view and aview from above, of the so formed unit.

FIG. 3A is a schematic illustration of the manner of production of acardboard-based unit according to a further embodiment of thedisclosure.

FIG. 3B shows a cardboard-based unit according to that embodiment.

FIG. 3C shows a side view of the unit of FIG. 3B.

FIG. 4 shows a front view of a cardboard-based unit according to anotherembodiment of the disclosure, which similar on overall shape to that ofFIG. 3B, with some functional cut-outs.

FIG. 5A is a front view of a cardboard panel with marked segments to becut-out prior to forming of the cardboard-based unit according toanother embodiment of the disclosure.

FIG. 5B shows the panel of FIG. 5A with segments cut-out and afterpositioning of the elongated members.

FIG. 5C shows a front view of the cardboard-based unit formed from thepanel of FIG. 5B.

FIGS. 6A-6B are schematic representations showing a perspective view andfront view, respectively, of a balance bike according to an embodimentof the invention.

FIGS. 7A-7H are schematic illustrations of steps in the manufacture ofthe body of a balance bike.

FIGS. 8A-8H are schematic illustrations of steps in the manufacture ofthe handlebar and fork assembly.

DETAILED DESCRIPTION OF EMBODIMENTS

The disclosure will now be illustrated below with reference to a numberof embodiments, schematically represented in the attached drawings. Inthe description below, FIG. 1 (namely 1A, 1B and 1C) relate to oneembodiment, and each of FIGS. 2, 3, 4 and 5 relate to differentembodiments. The different components of these embodiments are eachindicated by a three digit numeral, the first digit given according tothe figure in which they appear (for example, in FIG. 1 the numerals allbegin with “1”; whereas in FIG. 2 with the numeral “2”); while the lasttwo digits are specific for the component. In different figures likecomponents are indicated by a three digit numeral having the same lasttwo digits. By way of example, component 102 in FIGS. 1A and 1B is like(having similar function to) component 202 in FIGS. 2A and 2B. Such likecomponents may not be described each time and the reader is directed tolook into the description of the corresponding component in otherembodiments.

It should be noted that for the purpose of illustration, some dimensionswere drawn out of proportion. By way of example, in some figures acardboard panel is shown, from which a cardboard-based unit is produced.The panel is shown to have a thickness that is out of proportion of thethickness of at least some of the actual panel to be used in accordancewith the disclosure. The out of proportion thickness is for illustrationpurposes only as had it been drawn to proportion, it may have been moredifficult to view it in the drawings.

Reference is first being made to FIG. 1A showing a cardboard panel 100associated with two elongated members 102, 104 positioned oncorresponding parallel lines 106, 108, on a first face 140 of panel 100,equidistant from respective opposite edges 110, 112 (lines 106,108 areimaginary lines that do not exist in the actual panel). Elongatedmembers 102, 104, that are parallel to one another, separate betweenrespective flanking portions 114, 116 and a central portion 118 of thepanel.

In order to form a cardboard-based unit according to an embodiment ofthe disclosure, panel 100 is folded along lines 106, 108, as representedby arrows 106A, 108A such that portions thereof 120, 122 along andflanking lines 106, 108 wrap around and envelope tightly the elongatedmembers 102, 104, such that in the eventually formed unit, as seen inFIGS. 1B and 1C, portions 114, 116 are tightly associated at their firstface, e.g. through use of adhesive, with the first face of portion 118.

In the formed unit shown in FIGS. 1B and 1C, two elements can beidentified: two parallel, elongated, core-envelope elements 130, 132that define edges of the unit with a planar bi-layer element 134extending therebetween. Also, in this embodiment, panel edges 110, 112are brought into close proximity with one another. In this way, theformed cardboard panel defines a closed loop configuration about the twoelongated members.

The elongated members 102, 104 in this embodiment and those describedbelow have a circular cross-section. In some embodiments they may haveother round cross-sections, e.g. elliptical, oval.

The elongated, core-envelope elements 130,132, as also the otherelongated, core-envelope elements in the embodiments described below,have rounded edges which are a result of the forming process. However,through the use of appropriate dies or molds, the edges may bepress-formed to have other forms, e.g. rectangular. The cardboard panelmay, by one embodiment, be a corrugated or honeycomb cardboard panel.However, the disclosure is not limited to cardboard panels of this type.

Reference is now being made to FIGS. 2A-2C which illustrates a unitaccording to another embodiment (FIGS. 2B and 2C) and the manner offorming such a unit (FIG. 2A). As distinct from the embodiments of FIGS.1A-1C, according to those of FIGS. 2A-2C the cardboard panel is formedinto a shape resembling an “S”, rather than a closed loop.

In describing the embodiments of FIGS. 2A-2C, in order to facilitatedescription, reference will be made to two opposite faces of the paneldesignated as a first face 240 and a second opposite face 242.

As can be seen in FIG. 2A, elongated member 202 is associated with firstface 240 (positioned along line 206 parallel to edge 210) and elongatedmember 204 (parallel to elongated member 202) is associated with thesecond face 242 (positioned along line 208 parallel to edge 212).

As illustrated in FIG. 2A, lines 206, 208 define three portions ofsubstantially the same widths, including two flanking portions 214, 216,and a central portion 218. The panel 200 is formed by folding it alongline 206 in the direction represented by arrow 206A and in the oppositedirection along line 208 in the direction represented by arrow 208A.Eventually the so-formed cardboard-based unit, seen in FIGS. 2B-2C hastwo parallel, elongated, core-envelope elements 230, 232 at oppositeends of an overall substantially planar 3-layer element 234.

In the two embodiments of FIGS. 1A-2C, as previously described, parallelelongated members 102, 104 and 202, 204 (corresponding to elongatedcore-envelope elements 130, 132 and 230, 232) extend the entire lengthof the original cardboard panel and hence along the entire length of theformed cardboard-based unit. However, in some embodiments, such membersmay extend only the partial length, typically the majority of the lengthof the panel. According to another embodiment, rather than a singleelongated member in said elongated, core-envelope element, two or moreelongated members, arranged along the same axis, may be comprised withinthe elongated elements. In other words, the elongated member, in thiscase, is defined by a number of individual segments that may all be ofthe same or a different length. Such segments may be positioned suchthat an end of one is position adjacent an end of another; or suchsegments may, at times, be spaced apart from one another. The differentsegments may be made of the same or a different material. While suchsegments will typically have the same cross-sectional shapes, they may,at times, have different cross-sectional shapes.

Another cardboard-based unit and the manner in which it is formed areshown in FIGS. 3A-3C, which has a somewhat more complex design than thatof the preceding illustrated embodiments.

Turning now to FIG. 3A, a cardboard panel 300 and three elongatedmembers 302, 304, 350 can be seen. Elongated members 302, 304 aresituated parallel to one another and to edges 310, 312, along lines 306,308; and elongated member 350 is positioned parallel to edge 358,namely, oriented normal to elongated members 302, 304. Cardboard panel300 is cut along lines 306B, 308B which extend parallel to edge 358 fromrespective edges 310, 312 to respective lines 306, 308.

The flanking portions 314, 316 defined between lines 306, 308 andrespective cuts 306B, 308B are folded in the direction of arrows 306A,308A, in a similar manner to that described with respect to FIG. 1A, toeventually form, in the unit shown in FIG. 3B, a vertical structure 370with a bi-layer element defined between two parallel, elongatedcore-envelope elements 330, 332 at the edges thereof. The top portion354 of the cardboard panel, defined between lines 352 and edge 358, isthen folded along line 352 and over elongated member 350 in thedirection of arrow 352A to form a transverse elongated, core-envelopeelement 372. As can best be seen in FIG. 3C, the cardboard panel portionextending down from element 372 is integral with the central portion ofthe panel in structure 370.

Turning now to FIG. 4, showing a cardboard-based unit according toanother embodiment of the disclosure, having the overall shape as thatshown in FIGS. 3B and 3C. As can be seen, the unit in FIG. 4 differsfrom that of FIG. 3B by having two cut-outs voids 476, 478 that may becut-out after forming the unit of FIG. 3B. The unit may serve as a frontelement of a tricycle in which cut-out 478 accommodates a front wheel ofa tricycle, the wheel received through axle holders embedded in thebottom part of element 470 (not shown in this Fig. but will beillustrated further below); while cut-out 478 is articulated to the rearpart of a tricycle via a vertical axle receptacle embedded in element470 (not shown but will be illustrated in FIGS. 5B and 5C).

In some distinction from unit of FIG. 4, the cutouts may also bepre-formed in the panel. This is illustrated in FIG. 5. The cardboardpanel 500 seen in FIG. 5A has an overall rectangular shape, but severalpieces thereof, drawn as shadows, are cut out to yield the pre-formedpanel shown in FIG. 5B.

Similar as in the case of FIG. 3A, elongated members 502, 504 arepositioned along parallel, vertical lines 506, 508 and another elongatedmember 550 is positioned along line 552 normal to lines 506, 508. Shortaxle receptacles 580, 582 are placed close to the bottom end of portions518A, 518B, defined at the two sides of the cut-out 578, which aretypically hollow plastic tube segments for receiving respective ends ofthe axles of the front wheel of a tricycle. Also placed at thecardboard's first face are two vertical segments 584, 586, which may bealso hollow plastic tubes, and serve for articulation to the main bodyof a tricycle. The pre-formed panel is then folded about the elongatedmember in the direction represented by arrows 506A, 508A and 552A andthen, after adhering opposite cardboard faces to one another, thecardboard-based unit shown in FIG. 5C is formed.

Shown in FIGS. 6A-6B is a balance bike 600 having body 602, fork andhandlebar and fork assembly 604, seat 606, and front and rear wheels608, 610. The primary material out of which the balance bike 600 iscardboard; main exception include the wheels and some elements to bedescribed below that include the axles, the elongated members, thebushings and the pins.

As can further be seen in FIGS. 6A-6B, body 602 is composed of twoplanar body elements 612, 614 that define each a vertical plane, and areessentially mirror images of one another. Elements 612, 614 are attachedto one another at the front end portion 616 to define a front body block617 and diverge towards the rear end 618 defining between them a bodyspace 620, which widens towards the rear end.

As will further be explained, embedded in front body block 617 is a setof co-axial bushings (not seen in FIGS. 6A-6B but will be describedbelow and illustrated in other Figs.) which accommodate a fork pivot(also to be described below) that provides for rotational engagementbetween the fork assembly 604 and body 602, permitting a child riderholding handlebar 622 to steer the front wheel 608. Fitted within thebody space 620 is a stem 624 of seat 606, which is held in position bypins 626 that cross between the two body elements 612, 614 and throughstem 624. Wheels 608, 610 are rotationally coupled to respective fork605 and rear end 618 of body 602, through respective axles 628, 630.

The manner in which the body, as well as the fork assembly, isconstructed and hence also their constituents will now be described withreference to FIGS. 7A-7H and 8A-8H.

FIGS. 7A-7H illustrate the manner of construction of body 602, of whichFIGS. 7A-7G illustrate steps for constructing one of body elements 612,614. At a first step, a cardboard panel 700 having a general rectangularshape is provided and a groove 702 is formed at about the midline 704(represented by a dotted line) to thereby define two portions (A) ofsubstantially the same dimensions. The cardboard panel may, for example,be corrugated or honeycombed cardboard, e.g. of 10-14 mm, 11-13 mm or attimes 12 mm thickness.

A high density cardboard panel 706, typically a 600 g/m² cardboardsheet, having the same dimensions as portions A, shown in FIG. 7B, isprovided and a thin layer of glue is spread on both of its faces. Panel706 is then integrated with panel 700, which is folded about the midline704, to embrace and tightly associate through adherence to panel 706, asseen in FIG. 7C. This thus brings to the formation of the three-layeredstructure 710 with two external layers 708A, 708B of low densitycardboard, e.g. corrugated or honeycombed, and an internal layer of highdensity cardboard. This three-layered structure is rigid and hasload-bearing characteristics of a unit of the second aspect.

At a next step structure 710 is shaped to the intended body shape toachieve the desired form, as shown in FIG. 7D. Then, as represented inFIG. 7E, the edges of the structure, other than edge 712 which isdefined by fold 704, are then layered with a cardboard or paper strip714.

A horizontal bore 716 is then formed at one end that will become therear end of the body, and a vertical groove 718 having two peripheralwide portions 720A, 720B linked by a narrow portion 722 is formed at theother end, as seen in FIG. 7F. Then, as seen in FIG. 7G, two plasticbushings 724A, 724B are fitted into portions 720A and 720B,respectively.

Another of elements 612, 614, which is a mirror image to the firstelement is then prepared by identical steps and the two are attached tomone another at their front end portion to form body 602 with a frontbody block 617, with a bore 725 that is defined by bushings 724A and724B, as seen in FIG. 7H. Two plastic bushings 726, 728 are then fittedinto openings 716; these plastic bushings being intended to receive axle630 of rear wheel 610. At the next step (not shown) two lateral openingsare formed in each of elements 612, 614 to accommodate seat holding pins626, 628.

Reference is now being made to FIGS. 8A-8H illustrating the manner ofproduction and the structure of the fork assembly 604.

These depressions define a central segment 830 and two flanking segments832, 834. Also formed are two short longitudinal grooves 806, 808 atabout midline 810 of the panel; and two lateral grooves at the bottomend of the panel crossing depressions 802, 804, having central segments812A, 814A and lateral segments 812B, 814B.

As can be seen in FIG. 8B, longitudinal members that are constituted byrods 816, 818 are fitted into depressions 802 and 804, respectively, therods spanning the entire length of the grooves and having, respective,top portions 816A and 816B that project out of the top edge of thepanel. Rods 816, 818 are typically, but not exclusively, made of wood,cardboard or plastic but may also be made of metal and many othermaterials. As can also be seen, bushing 820 is fitted at the bottom endof groove 806 and bushing 822 is fitted into groove 808. Furthermore,bushings 824 and 826 are fitted into the two central groove segments812A and 814A, respectively. Rods 816, 818 and bushings 820, 822, 824and 826 are typically secured in position through the use of anadhesive.

At the next step, seen in FIG. 8C, a high density cardboard panel, whichmay have similar characteristics to the high density cardboard describedabove with regard to the body, is then formed to have the shape matchingthat of the panel's central segment 830. The high density cardboardpanel is then attached to the central segment 830, typically throughapplication of an adhesive.

The two lateral segments 832, 834 are then folded in the direction ofarrows X1 and X2 to form the structure 840, seen in FIG. 8D, in whichthe lateral edges of segments 832, 834 are associated with one anotherat the midline 810 to thereby define a three-layered structure withexternal low density cardboard layers. As can also be seen, after suchfolding, groove segments 812A, 813B jointly define a bore 842; amirror-image opening, of course, also exists at the other end (not seenin this Figure).

At the next step, rectangular section 848 is cut out from a mid-portionof structure 840 to define an opening 848A and an elongated section 850with a curved upper end is cut from a bottom portion of structure 840 todefine a wheel space 850A, to thereby form the fork unit 605, seen inFIG. 8E.

Visible in FIG. 8E is also bore 846, defined by bushing 826 which isrevealed by the cut out of portion 848 and is coaxial with bore 842. Cutout of portion 850 reveals bore 854 defined by bushing 822 which iscoaxial with bore 852 defined by groove 806 (which accommodates at itsbottom portion bushing 820). Bushings 824 and 826 within bores 842 and846, respectively, are intended to accommodate pivot 630. Bushings 820and 822 within respective bores 852 and 854 are intended to accommodateaxle 856, as seen in FIG. 8, to thereby couple the body and the fork ina pivotal manner to enable for steering, as described above.

Handlebar 622 is seen in FIG. 8G and includes a cardboard cylinder 858formed with three bores 860, 862, 864, the latter accommodating pin 866.The bore and the pin are positioned and dimensioned such that bores 860and 862 can accommodate projections 816A and 818A of rods 816 and 818,respectively, while the pin fits into bore 852. The length of pin 866 issuch that once inserted into bore 852, it will fit into the space abovebushing 820. By combining the handlebar with the fork, assembly 604 isformed, seen in FIG. 8H.

By inserting body block 617 into opening 848A and then inserting pivot630 through bore 852 to pass through the bore 725 in body block 617, thebody 602 becomes pivotally coupled to assembly 604. The front wheel 608may then be fitted into the wheel space 850A and rotationally coupled tothe fork through axle 630.

1. A planar structural unit, comprising a planar multi-layered elementcomprising two or more layers of low density cardboard that are adheredone to the other and being formed from a single low density cardboardpanel; and the planar multi-layered element having edges defined bycore-envelope elements that are integral with the planar multi-layeredelement, the core-envelope elements comprising enveloping portions ofthe low density cardboard that are wrapped about and tightly envelopingtwo or more elongated members.
 2. The unit of claim 1, wherein two ofsaid elongated core-envelope elements are parallel one to the other. 3.The unit of claim 1, wherein the planar multi-layered element comprisesa high density cardboard layer sandwiched between two layers oflow-density cardboard
 4. The unit of claim 1, wherein said elongatedmembers have a circular cross-section.
 5. The unit of claim 1, whereinsaid elongated members are made of wood, cardboard or plastic.
 6. Theunit of claim 1, wherein the low-density cardboard is corrugatedcardboard or honeycomb cardboard.
 7. The unit of claim 1, wherein twoflanking segments of the panel are folded over the elongated members andare associated with a central segment of the panel that is definedbetween said elongated members.
 8. The unit of claim 7, wherein theflanking segments are associated with the same face of the centralsegment, and wherein opposite edges of the panel, at the end of saidflanking segments, are proximal to one another.
 9. The unit of claim 7,wherein one or more portions of a face of one flanking segment areattached to corresponding one or more portions on the same face of saidcentral segment, and one or more portions of said second flankingsegment are attached to corresponding one or more portions of theopposite face of said central segment.
 10. The unit of claim 9, whereinone of the parallel elongated members is associated with one face of thepanel, and the other of the parallel elongated members is associatedwith the opposite face of the panel.
 11. The unit of claim 1, whereinsaid planar element comprises one or more voids.
 12. The unit of claim1, wherein the unit comprising one or more integral second core-envelopeelements oriented normal to said parallel elongated core-envelopeelements.